A Sam’s Club Exclusive - Smarty Pets Large Automatic Pet Door Value Kit includes an Automatic Pet Door complete with U4 Collar, and Rechargeable Back-up Battery. Engineered for performance, design, value and extreme reliability, Smarty Pets electronic pet doors are fully automatic. They are motor driven and open under their own power. They feature a translucent door panel made of a new super-strength bulletproof resin. When your pet approaches, the air-tight panel powers upward, into the stylish housing. The panel moves up and down and does not swing out so the panel is mounted in hermetically sealed vertical grooves making it completely air-tight, even in storm force winds. This mounting arrangement also makes it impossible for an intruder to kick it out. The result is a pet door that is easy to use for your pet and very secure against intruders and stray animals. The extra-large panel measures 12" X 16.25" for all pets up to a full 100-pounds! Operates on AC adapter (included), or rechargeable backup battery (included), which snaps into the battery compartment to keep your Smarty Pets door functioning in the case of a power outage. Purchase our optional battery charger kit (sold separately) if you wish to operate your Smarty Pets automatic pet door without an AC power connection.